NC State
A.R. Farmer. Analog computing techniques applied to papermaking. In Papermaking Systems and their Control, Trans. of the IVth Fund. Res. Symp. Oxford, 1969, (F. Bolam, ed.), pp 269–282, FRC, Manchester.


An examination of papermachine wet end fibre balance and stock flow equations reveals the interdependence of important papermaking parameters and the control strategy required to make changes in machine running conditions. To avoid breaks during any adjustment, the fibre and water balance of the wire must be controlled closely and any controlling device must incorporate some ` built in’ knowledge or mathematical model of the process . It is shown how analog computing elements can fulfil this requirement and thus provide a low cost alternative to a digital computer installation.

An analog computer control system has been in operation for 18 months on the No. 2 papermachine at the Grove Mill Paper Co. of New Mills. During this period, a 15 percent increase in production can be attributed directly to the use of the computer. Results given include a typical beta-gauge chart, showing the close control of basis weight and the sequence of events that occur during a grade change.

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